The 'Big Brother' housemates have become characters from 'Alice in Wonderland' for this week's shopping task.

Each of the ten contestants has a part from Lewis Carroll's offbeat fairy tale, and must stay in character over the next two days while completing tasks relevant to their roles.

The housemates have each assumed one of the following characters: Alice, Queen Of Hearts, Knave Of Hearts, The White Rabbit, The Cheshire Cat, The Mad Hatter and four Playing Cards.

The central character, Alice – played by Hira - will have to drink a potion and eat an oversized cake, to reveal a key which she will use to get into the Diary Room, which is to be 'shrunk'.

Alice will then only be allowed out of the room when she manages to produce real tears. To aid this, Big Brother will read sad stories and play sad music.

The Queen and Knave Of Hearts - Charlie and Marcus respectively - will become the house's resident pastry chefs, cooking a variety of tarts with varying fillings, some of which will be foul tasting, which the playing cards - Bea, Freddie, Lisa and David - will then have to eat in order to pass their part of the challenge.

Meanwhile the Cheshire Cat, Rodrigo, will have to produce a broad and genuine smile every time a song with the word 'Smile' in its title is played into the house. The cat must smile throughout the duration of the song, but could also fail the task if they smile while a song is not being played.

The White Rabbit in 'Alice in Wonderland' is obsessed with timing. The elected Rabbit, Siavash, will have to keep his pocket watch wound so it stays on time and be at the rabbit hutch for a series of 'appointments' which Big Brother will announce. The White Rabbit can be up to five minutes early for the meetings, but never late.

Lastly, the Mad Hatter, played by Sophie (Dogface) will have to learn how to differentiate between 25 different types of tea and pass a test on the second day in order to pass her part of task.

After the gruelling challenges the 'Alice in Wonderland' theme will culminate with a huge tea party for the housemates with alcohol served in teapots, sandwiches and cakes.